Image processing device, image processing method, and recording medium

1. An image processing device comprising: one or more memories storing instructions; and one or more processors configured to execute the instructions to: accept inputting of an operation for movement of a target object on a captured image, the captured image including at least one of a plurality of persons and a plurality of objects captured by a camera, the target object being indicated by a first image that is superimposed on the captured image based on specific camera parameters relating to a position and an attitude of the camera set on a real space; and present, based on the specific camera parameters, a trajectory of the target object on the captured image, the trajectory corresponding to the movement of the target object on the captured image and passing through at least one position on the captured image, the at least one position relating to the at least one of the plurality of persons and the plurality of objects, wherein the one or more processors are further configured to: accept the operation for movement by repeatedly accepting a designation of a first position on the captured image, generate, when the first position is designated, based on the specific camera parameters, a predetermined shape and a predetermined size on a real space of the target object, and a second position on the real space relating to the first position, the first image indicating the target object on the captured image appearing in a camera determined by the specific camera parameters when the target object is disposed in the second position, and present the generated first image in the first position on the captured image.

2. The image processing device according to claim 1 , wherein the one or more processors are further configured to: acquire height information of the second position, and calculate the second position based on the specific camera parameters, the first position, and the height information of the second position.

3. The image processing device according to claim 2 , wherein the one or more processors are further configured to acquire information indicating a height of a ground surface in a real space as the height information of the second position.

4. The image processing device according to claim 2 , wherein the one or more processors are further configured to acquire pieces of information of different heights for a plurality of areas on the captured image, respectively, as the height information of the second position.

5. The image processing device according to claim 1 , wherein the target object has a planar shape.

6. The image processing device according to claim 1 , wherein: the one or more processors are further configured to: accept inputting of a point or a line to the captured image; and display a second image indicating the point or the line upon mapping on a plane parallel to a ground surface, based on the specific camera parameters, a position on the captured image of the point or the line, and height information on a real space of the point or the line.

7. The image processing device according to claim 1 , wherein the target object is a virtual cubic.

8. The image processing device according to claim 1 , wherein the target object has a simplified shape and/or size representing the at least one of the plurality of persons and the plurality of objects.